*: Convert list_delete(struct list *) to ** to allow nulling

Convert the list_delete(struct list *) function to use
struct list **.  This is to allow the list pointer to be nulled.

I keep running into uses of this list_delete function where we
forget to set the returned pointer to NULL and attempt to use
it and then experience a crash, usually after the developer
has long since left the building.

Let's make the api explicit in it setting the list pointer
to null.

Cynical Prediction:  This code will expose a attempt
to use the NULL'ed list pointer in some obscure bit
of code.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

12 files changed, 42 insertions, 50 deletions

diff --git a/ospfd/ospf_apiserver.c b/ospfd/ospf_apiserver.c
index 252a5df0f..c1485abb8 100644
--- a/ospfd/ospf_apiserver.c
+++ b/ospfd/ospf_apiserver.c
@@ -180,7 +180,7 @@ void ospf_apiserver_term(void)
 
 	/* Free client list itself */
 	if (apiserver_list)
-		list_delete(apiserver_list);
+		list_delete_and_null(&apiserver_list);
 
 	/* Free wildcard list */
 	/* XXX  */
diff --git a/ospfd/ospf_ase.c b/ospfd/ospf_ase.c
index 877e4b7fb..1abb1a6a3 100644
--- a/ospfd/ospf_ase.c
+++ b/ospfd/ospf_ase.c
@@ -98,7 +98,7 @@ struct ospf_route *ospf_find_asbr_route(struct ospf *ospf,
 		}
 
 	if (chosen != rn->info)
-		list_delete(chosen);
+		list_delete_and_null(&chosen);
 
 	return best;
 }
@@ -761,7 +761,7 @@ void ospf_ase_external_lsas_finish(struct route_table *rt)
 		if ((lst = rn->info) != NULL) {
 			for (ALL_LIST_ELEMENTS(lst, node, nnode, lsa))
 				ospf_lsa_unlock(&lsa); /* external_lsas lst */
-			list_delete(lst);
+			list_delete_and_null(&lst);
 		}
 
 	route_table_finish(rt);
diff --git a/ospfd/ospf_interface.c b/ospfd/ospf_interface.c
index d8d7caa68..b57f8a4d3 100644
--- a/ospfd/ospf_interface.c
+++ b/ospfd/ospf_interface.c
@@ -509,7 +509,7 @@ static struct ospf_if_params *ospf_new_if_params(void)
 
 void ospf_del_if_params(struct ospf_if_params *oip)
 {
-	list_delete(oip->auth_crypt);
+	list_delete_and_null(&oip->auth_crypt);
 	bfd_info_free(&(oip->bfd_info));
 	XFREE(MTYPE_OSPF_IF_PARAMS, oip);
 }
diff --git a/ospfd/ospf_ism.c b/ospfd/ospf_ism.c
index f223a870d..25ab9cbe0 100644
--- a/ospfd/ospf_ism.c
+++ b/ospfd/ospf_ism.c
@@ -104,7 +104,7 @@ static struct ospf_neighbor *ospf_elect_dr(struct ospf_interface *oi,
 	else
 		DR(oi).s_addr = 0;
 
-	list_delete(dr_list);
+	list_delete_and_null(&dr_list);
 
 	return dr;
 }
@@ -144,8 +144,8 @@ static struct ospf_neighbor *ospf_elect_bdr(struct ospf_interface *oi,
 	else
 		BDR(oi).s_addr = 0;
 
-	list_delete(bdr_list);
-	list_delete(no_dr_list);
+	list_delete_and_null(&bdr_list);
+	list_delete_and_null(&no_dr_list);
 
 	return bdr;
 }
@@ -232,7 +232,7 @@ static int ospf_dr_election(struct ospf_interface *oi)
 		zlog_debug("DR-Election[2nd]: DR     %s", inet_ntoa(DR(oi)));
 	}
 
-	list_delete(el_list);
+	list_delete_and_null(&el_list);
 
 	/* if DR or BDR changes, cause AdjOK? neighbor event. */
 	if (!IPV4_ADDR_SAME(&old_dr, &DR(oi))
diff --git a/ospfd/ospf_lsa.c b/ospfd/ospf_lsa.c
index e5d4d3423..270021cab 100644
--- a/ospfd/ospf_lsa.c
+++ b/ospfd/ospf_lsa.c
@@ -3707,7 +3707,7 @@ int ospf_lsa_refresh_walker(struct thread *t)
 			&lsa); /* lsa_refresh_queue & temp for lsa_to_refresh*/
 	}
 
-	list_delete(lsa_to_refresh);
+	list_delete_and_null(&lsa_to_refresh);
 
 	if (IS_DEBUG_OSPF(lsa, LSA_REFRESH))
 		zlog_debug("LSA[Refresh]: ospf_lsa_refresh_walker(): end");
diff --git a/ospfd/ospf_opaque.c b/ospfd/ospf_opaque.c
index bc71e371b..5a1f28b03 100644
--- a/ospfd/ospf_opaque.c
+++ b/ospfd/ospf_opaque.c
@@ -113,7 +113,7 @@ void ospf_opaque_term(void)
 int ospf_opaque_type9_lsa_init(struct ospf_interface *oi)
 {
 	if (oi->opaque_lsa_self != NULL)
-		list_delete(oi->opaque_lsa_self);
+		list_delete_and_null(&oi->opaque_lsa_self);
 
 	oi->opaque_lsa_self = list_new();
 	oi->opaque_lsa_self->del = free_opaque_info_per_type;
@@ -125,7 +125,7 @@ void ospf_opaque_type9_lsa_term(struct ospf_interface *oi)
 {
 	OSPF_TIMER_OFF(oi->t_opaque_lsa_self);
 	if (oi->opaque_lsa_self != NULL)
-		list_delete(oi->opaque_lsa_self);
+		list_delete_and_null(&oi->opaque_lsa_self);
 	oi->opaque_lsa_self = NULL;
 	return;
 }
@@ -133,7 +133,7 @@ void ospf_opaque_type9_lsa_term(struct ospf_interface *oi)
 int ospf_opaque_type10_lsa_init(struct ospf_area *area)
 {
 	if (area->opaque_lsa_self != NULL)
-		list_delete(area->opaque_lsa_self);
+		list_delete_and_null(&area->opaque_lsa_self);
 
 	area->opaque_lsa_self = list_new();
 	area->opaque_lsa_self->del = free_opaque_info_per_type;
@@ -154,15 +154,14 @@ void ospf_opaque_type10_lsa_term(struct ospf_area *area)
 
 	OSPF_TIMER_OFF(area->t_opaque_lsa_self);
 	if (area->opaque_lsa_self != NULL)
-		list_delete(area->opaque_lsa_self);
-	area->opaque_lsa_self = NULL;
+		list_delete_and_null(&area->opaque_lsa_self);
 	return;
 }
 
 int ospf_opaque_type11_lsa_init(struct ospf *top)
 {
 	if (top->opaque_lsa_self != NULL)
-		list_delete(top->opaque_lsa_self);
+		list_delete_and_null(&top->opaque_lsa_self);
 
 	top->opaque_lsa_self = list_new();
 	top->opaque_lsa_self->del = free_opaque_info_per_type;
@@ -183,8 +182,7 @@ void ospf_opaque_type11_lsa_term(struct ospf *top)
 
 	OSPF_TIMER_OFF(top->t_opaque_lsa_self);
 	if (top->opaque_lsa_self != NULL)
-		list_delete(top->opaque_lsa_self);
-	top->opaque_lsa_self = NULL;
+		list_delete_and_null(&top->opaque_lsa_self);
 	return;
 }
 
@@ -287,16 +285,16 @@ static void ospf_opaque_funclist_term(void)
 	struct list *funclist;
 
 	funclist = ospf_opaque_wildcard_funclist;
-	list_delete(funclist);
+	list_delete_and_null(&funclist);
 
 	funclist = ospf_opaque_type9_funclist;
-	list_delete(funclist);
+	list_delete_and_null(&funclist);
 
 	funclist = ospf_opaque_type10_funclist;
-	list_delete(funclist);
+	list_delete_and_null(&funclist);
 
 	funclist = ospf_opaque_type11_funclist;
-	list_delete(funclist);
+	list_delete_and_null(&funclist);
 	return;
 }
 
@@ -616,7 +614,7 @@ static void free_opaque_info_per_type(void *val)
 	}
 
 	OSPF_TIMER_OFF(oipt->t_opaque_lsa_self);
-	list_delete(oipt->id_list);
+	list_delete_and_null(&oipt->id_list);
 	XFREE(MTYPE_OPAQUE_INFO_PER_TYPE, oipt);
 	return;
 }
diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index 015eac096..36583a63e 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -519,7 +519,7 @@ int ospf_ls_upd_timer(struct thread *thread)
 
 		if (listcount(update) > 0)
 			ospf_ls_upd_send(nbr, update, OSPF_SEND_PACKET_DIRECT);
-		list_delete(update);
+		list_delete_and_null(&update);
 	}
 
 	/* Set LS Update retransmission timer. */
@@ -1572,7 +1572,7 @@ static void ospf_ls_req(struct ip *iph, struct ospf_header *ospfh,
 		/* Verify LSA type. */
 		if (ls_type < OSPF_MIN_LSA || ls_type >= OSPF_MAX_LSA) {
 			OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_BadLSReq);
-			list_delete(ls_upd);
+			list_delete_and_null(&ls_upd);
 			return;
 		}
 
@@ -1581,7 +1581,7 @@ static void ospf_ls_req(struct ip *iph, struct ospf_header *ospfh,
 				       adv_router);
 		if (find == NULL) {
 			OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_BadLSReq);
-			list_delete(ls_upd);
+			list_delete_and_null(&ls_upd);
 			return;
 		}
 
@@ -1615,7 +1615,7 @@ static void ospf_ls_req(struct ip *iph, struct ospf_header *ospfh,
 			ospf_ls_upd_send(nbr, ls_upd,
 					 OSPF_SEND_PACKET_INDIRECT);
 
-		list_delete(ls_upd);
+		list_delete_and_null(&ls_upd);
 	} else
 		list_free(ls_upd);
 }
@@ -1758,7 +1758,7 @@ static void ospf_upd_list_clean(struct list *lsas)
 	for (ALL_LIST_ELEMENTS(lsas, node, nnode, lsa))
 		ospf_lsa_discard(lsa);
 
-	list_delete(lsas);
+	list_delete_and_null(&lsas);
 }
 
 /* OSPF Link State Update message read -- RFC2328 Section 13. */
@@ -2159,7 +2159,7 @@ static void ospf_ls_upd(struct ospf *ospf, struct ip *iph,
 #undef DISCARD_LSA
 
 	assert(listcount(lsas) == 0);
-	list_delete(lsas);
+	list_delete_and_null(&lsas);
 }
 
 /* OSPF Link State Acknowledgment message read -- RFC2328 Section 13.7. */
@@ -3774,7 +3774,7 @@ void ospf_ls_upd_send_lsa(struct ospf_neighbor *nbr, struct ospf_lsa *lsa,
 	listnode_add(update, lsa);
 	ospf_ls_upd_send(nbr, update, flag);
 
-	list_delete(update);
+	list_delete_and_null(&update);
 }
 
 /* Determine size for packet. Must be at least big enough to accomodate next
@@ -3918,8 +3918,7 @@ static int ospf_ls_upd_send_queue_event(struct thread *thread)
 
 		/* list might not be empty. */
 		if (listcount(update) == 0) {
-			list_delete(rn->info);
-			rn->info = NULL;
+			list_delete_and_null((struct list **)&rn->info);
 			route_unlock_node(rn);
 		} else
 			again = 1;
diff --git a/ospfd/ospf_ri.c b/ospfd/ospf_ri.c
index f9e346b1d..d5769c866 100644
--- a/ospfd/ospf_ri.c
+++ b/ospfd/ospf_ri.c
@@ -188,11 +188,9 @@ static int ospf_router_info_unregister()
 void ospf_router_info_term(void)
 {
 
-	list_delete(OspfRI.pce_info.pce_domain);
-	list_delete(OspfRI.pce_info.pce_neighbor);
+	list_delete_and_null(&OspfRI.pce_info.pce_domain);
+	list_delete_and_null(&OspfRI.pce_info.pce_neighbor);
 
-	OspfRI.pce_info.pce_domain = NULL;
-	OspfRI.pce_info.pce_neighbor = NULL;
 	OspfRI.enabled = false;
 
 	ospf_router_info_unregister();
diff --git a/ospfd/ospf_route.c b/ospfd/ospf_route.c
index ca851ec75..cc7c6d266 100644
--- a/ospfd/ospf_route.c
+++ b/ospfd/ospf_route.c
@@ -54,7 +54,7 @@ struct ospf_route *ospf_route_new()
 void ospf_route_free(struct ospf_route * or)
 {
 	if (or->paths)
-		list_delete(or->paths);
+		list_delete_and_null(&or->paths);
 
 	XFREE(MTYPE_OSPF_ROUTE, or);
 }
@@ -902,7 +902,7 @@ void ospf_prune_unreachable_routers(struct route_table *rtrs)
 				zlog_debug("Pruning router node %s",
 					   inet_ntoa(rn->p.u.prefix4));
 
-			list_delete(paths);
+			list_delete_and_null(&paths);
 			rn->info = NULL;
 			route_unlock_node(rn);
 		}
diff --git a/ospfd/ospf_spf.c b/ospfd/ospf_spf.c
index 5e5742608..65437dba9 100644
--- a/ospfd/ospf_spf.c
+++ b/ospfd/ospf_spf.c
@@ -210,12 +210,10 @@ static void ospf_vertex_free(void *data)
 	// assert (listcount (v->parents) == 0);
 
 	if (v->children)
-		list_delete(v->children);
-	v->children = NULL;
+		list_delete_and_null(&v->children);
 
 	if (v->parents)
-		list_delete(v->parents);
-	v->parents = NULL;
+		list_delete_and_null(&v->parents);
 
 	v->lsa = NULL;
 
@@ -1089,7 +1087,7 @@ void ospf_rtrs_free(struct route_table *rtrs)
 			for (ALL_LIST_ELEMENTS(or_list, node, nnode, or))
 				ospf_route_free(or);
 
-			list_delete(or_list);
+			list_delete_and_null(&or_list);
 
 			/* Unlock the node. */
 			rn->info = NULL;
diff --git a/ospfd/ospf_te.c b/ospfd/ospf_te.c
index 294ffe48b..5f300daba 100644
--- a/ospfd/ospf_te.c
+++ b/ospfd/ospf_te.c
@@ -166,8 +166,7 @@ static int ospf_mpls_te_unregister()
 
 void ospf_mpls_te_term(void)
 {
-	list_delete(OspfMplsTE.iflist);
-	OspfMplsTE.iflist = NULL;
+	list_delete_and_null(&OspfMplsTE.iflist);
 
 	ospf_delete_opaque_functab(OSPF_OPAQUE_AREA_LSA,
 				   OPAQUE_TYPE_TRAFFIC_ENGINEERING_LSA);
diff --git a/ospfd/ospfd.c b/ospfd/ospfd.c
index 507c97d97..24d3abf2a 100644
--- a/ospfd/ospfd.c
+++ b/ospfd/ospfd.c
@@ -620,7 +620,7 @@ static void ospf_finish_final(struct ospf *ospf)
 	for (ALL_LIST_ELEMENTS(ospf->vlinks, node, nnode, vl_data))
 		ospf_vl_delete(ospf, vl_data);
 
-	list_delete(ospf->vlinks);
+	list_delete_and_null(&ospf->vlinks);
 
 	/* Remove any ospf interface config params */
 	for (ALL_LIST_ELEMENTS_RO(vrf_iflist(ospf->vrf_id), node, ifp)) {
@@ -734,9 +734,9 @@ static void ospf_finish_final(struct ospf *ospf)
 		ospf_ase_external_lsas_finish(ospf->external_lsas);
 	}
 
-	list_delete(ospf->areas);
-	list_delete(ospf->oi_write_q);
-	list_delete(ospf->oiflist);
+	list_delete_and_null(&ospf->areas);
+	list_delete_and_null(&ospf->oi_write_q);
+	list_delete_and_null(&ospf->oiflist);
 
 	for (i = ZEBRA_ROUTE_SYSTEM; i <= ZEBRA_ROUTE_MAX; i++) {
 		struct list *ext_list;
@@ -852,7 +852,7 @@ static void ospf_area_free(struct ospf_area *area)
 	ospf_lsa_unlock(&area->router_lsa_self);
 
 	route_table_finish(area->ranges);
-	list_delete(area->oiflist);
+	list_delete_and_null(&area->oiflist);
 
 	if (EXPORT_NAME(area))
 		free(EXPORT_NAME(area));
@@ -1276,7 +1276,7 @@ void ospf_ls_upd_queue_empty(struct ospf_interface *oi)
 		if ((lst = (struct list *)rn->info)) {
 			for (ALL_LIST_ELEMENTS(lst, node, nnode, lsa))
 				ospf_lsa_unlock(&lsa); /* oi->ls_upd_queue */
-			list_delete(lst);
+			list_delete_and_null(&lst);
 			rn->info = NULL;
 		}